Improvement in beams and rafters



PATENT OFFICE.

EDWARD T. POTTER, OE NEW YORK, N. Y.

IMPROVEMENT |N BEANS AND RAFTERS.

Specification forming part of Letters Patent No. 146,779, dated January 27, 1874; application filed September 10, 1873.

To all whom it may concern:

Beit known that I, EDWARD T. POTTER, of the city, county, and State of lNew York, have invented a new and useful Improvement in Beams and Batters; and l do hereby decla-re the ibllowing to be a full, clear, and exact description of the same, reference being had to the annexed drawing, making part oi' this specification, in which- Figure l is a longitudinal section ot' the beam or rafter in which my invention is cmbodied. Fig. 2 a cross section oi' said beam, and Fi 3 is a modified form oi' said invention.

lt is Well known that ii' a tube be loaded transversely its power to resist the weight will lessen as the deflection increases, or as its walls are forced nearer and nearer together, `until the tube be flattened; but ii' the walls oi' the tube be kept apart and deflection avoided, its strength will be greatly increased-will, in fact, be equal to the tensile strength Ot' the wall ofthe tube on its convex side.

Theobject of my invention is the production ot' a very light but stiii' beam or raftcr, to be used in the construction Ot' buildings, by making said beam or rat'ter in the form ot' a tube braced or trussed to obtain the maximum strength of the material in that form; and my invention consists oi' a metal tube braced or trussed transversely to stiii'en it, lessen its detlection, and keep it from collapsing.

In the drawing, A A represent tubes made of metal, in Which there are disks or plugs of wood or metal driven, as shown by B B, and

around the outside of which a band, C C, is

shrunk, forged, or raised, to hold the wall of the tube lirmly on the disk. The effect of this trussing is to divide the tube in sections, and confer, in a great measure, the strength of a short tube upon a long one.

There may be as many of these disks and i bands as, inthe judgment of the maker or user, may be necessary. They should be as near together, however, as they can be., having due regard to the Weight of the structure, as the strength of the tube Will be increased as the disks and bands are multiplied, until their weight is more than equal to the strength they confer.

After the diskhas been duly inserted and the band applied, I vpropose to drive a nail through the band and tube into the disk, in the manner shown, should I deem it necessary, the beam and tube being first duly perforated to admit the nail. The tubes may, of course, be riveted, drawn, welded, or lapped up, as shown in Fig. In using this style of rafter or beam in the construction of any extended work, they must, ot' course, be joined or braced by means ot' struts, shown by D. To accomplish this no particular form of union is necessary; but the one shown in the drawing answers a very good purpose, and is submitted as a good form for adoption. .A

These tubes may, of course, be combined together in various ways in the formation ofthe beams or raft-ers, and they are intended to be used in all sorts ot' iron or wooden structures. My intention is to patent the tube and use it wherever it may be desirable.

Having now described the object and use of my invention, I claim and desire'to secure by Letters Patent- The external band C C and the internal disk B B, in combination With the tube or hollow cylinder, for the purpose of trussing or bracing the same, substantially as described.

`EDVVJiXRD T.. POTTER. Titnesses i AMos BROADNAX, STURGEs ALLEN. 

